There are many mechanisms that include one or more shaft-mounted devices. The shaft-mounted devices are, in many instances, secured on the shaft via a threaded nut, such as a spanner nut. That is, the threaded nut is threaded onto mating threads that are formed on the shaft, and engages, either directly or indirectly, the shaft-mounted device. The threaded nut may be torqued to a predetermined torque, whereby frictional forces between the shaft and the threaded nut provide a passive locking means to prevent rotation of the threaded nut.
In some instances, it may be desirable to provide a secondary (e.g., back-up), positive anti-rotation locking device for the threaded nut. However, the space envelope provided for such devices can be limited, thereby limiting the possible choices for implementing such devices. Moreover, some known anti-rotation locking devices, such as T-locks, that may potentially fit within such limited space envelopes, undesirably rely on deformation to provide the anti-rotation locking feature.
Hence, there is a need for a positive locking anti-rotation device that can be used in relatively small space envelopes, and that do not rely on deformation to provide the anti-rotation locking feature. The present invention addresses at least these needs.